/*-
 * Copyright (c) 2010 Isilon Systems, Inc.
 * Copyright (c) 2010 iX Systems, Inc.
 * Copyright (c) 2010 Panasas, Inc.
 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef	_LINUX_BITOPS_H_
#define	_LINUX_BITOPS_H_

#include <sys/param.h>
#include <barrelfish/barrelfish.h>

#include <linux/kernel.h>
#include <linux/errno.h>


#ifdef __LP64__
#define	BITS_PER_LONG		64
#else
#define	BITS_PER_LONG		32
#endif
#define	BIT_MASK(n)		(~0UL >> (BITS_PER_LONG - (n)))
#define	BITS_TO_LONGS(n)	howmany((n), BITS_PER_LONG)
#define BIT_WORD(nr)		((nr) / BITS_PER_LONG)

#define BITS_PER_BYTE           8

static inline int __ffs(int mask) {
	return (ffs(mask) - 1);
}
/*
 static inline int
 __fls(int mask)
 {
 return (fls(mask) - 1);
 }
 */
// static int ffsl(long mask) {
// 	int bit;
//
// 	if (mask == 0)
// 		return (0);
// 	for (bit = 1; !(mask & 1); bit++)
// 		mask = (unsigned long) mask >> 1;
// 	return (bit);
// }

static inline int __ffsl(long mask) {
	return (ffsl(mask) - 1);
}
/*
 static inline int
 __flsl(long mask)
 {
 return (flsl(mask) - 1);
 }

 */
#define	ffz(mask)	__ffs(~(mask))

static inline int get_count_order(unsigned int count) {
	int order;

	order = fls(count) - 1;
	if (count & (count - 1))
		order++;
	return order;
}

static inline unsigned long find_first_bit(unsigned long *addr,
		unsigned long size) {
	long mask;
	int bit;

	for (bit = 0; size >= BITS_PER_LONG; size -= BITS_PER_LONG, bit +=
	BITS_PER_LONG, addr++) {
		if (*addr == 0)
			continue;
		return (bit + __ffsl(*addr));
	}
	if (size) {
		mask = (*addr) & BIT_MASK(size);
		if (mask)
			bit += __ffsl(mask);
		else
			bit += size;
	}
	return (bit);
}

static inline unsigned long find_first_zero_bit(unsigned long *addr,
		unsigned long size) {
	long mask;
	int bit;

	for (bit = 0; size >= BITS_PER_LONG; size -= BITS_PER_LONG, bit +=
	BITS_PER_LONG, addr++) {
		if (~(*addr) == 0)
			continue;
		return (bit + __ffsl(~(*addr)));
	}
	if (size) {
		mask = ~(*addr) & BIT_MASK(size);
		if (mask)
			bit += __ffsl(mask);
		else
			bit += size;
	}
	return (bit);
}
/*
 static inline unsigned long
 find_last_bit(unsigned long *addr, unsigned long size)
 {
 long mask;
 int offs;
 int bit;
 int pos;

 pos = size / BITS_PER_LONG;
 offs = size % BITS_PER_LONG;
 bit = BITS_PER_LONG * pos;
 addr += pos;
 if (offs) {
 mask = (*addr) & BIT_MASK(offs);
 if (mask)
 return (bit + __flsl(mask));
 }
 while (--pos) {
 addr--;
 bit -= BITS_PER_LONG;
 if (*addr)
 return (bit + __flsl(mask));
 }
 return (size);
 }
 */
static inline unsigned long find_next_bit(unsigned long *addr,
		unsigned long size, unsigned long offset) {
	long mask;
	int offs;
	int bit;
	int pos;

	if (offset >= size)
		return (size);
	pos = offset / BITS_PER_LONG;
	offs = offset % BITS_PER_LONG;
	bit = BITS_PER_LONG * pos;
	addr += pos;
	if (offs) {
		mask = (*addr) & ~BIT_MASK(offs);
		if (mask)
			return (bit + __ffsl(mask));
		if (size - bit <= BITS_PER_LONG)
			return (size);
		bit += BITS_PER_LONG;
		addr++;
	}
	for (size -= bit; size >= BITS_PER_LONG; size -= BITS_PER_LONG, bit +=
			BITS_PER_LONG, addr++) {
		if (*addr == 0)
			continue;
		return (bit + __ffsl(*addr));
	}
	if (size) {
		mask = (*addr) & BIT_MASK(size);
		if (mask)
			bit += __ffsl(mask);
		else
			bit += size;
	}
	return (bit);
}

static inline unsigned long find_next_zero_bit(unsigned long *addr,
		unsigned long size, unsigned long offset) {
	long mask;
	int offs;
	int bit;
	int pos;

	if (offset >= size)
		return (size);
	pos = offset / BITS_PER_LONG;
	offs = offset % BITS_PER_LONG;
	bit = BITS_PER_LONG * pos;
	addr += pos;
	if (offs) {
		mask = ~(*addr) & ~BIT_MASK(offs);
		if (mask)
			return (bit + __ffsl(mask));
		if (size - bit <= BITS_PER_LONG)
			return (size);
		bit += BITS_PER_LONG;
		addr++;
	}
	for (size -= bit; size >= BITS_PER_LONG; size -= BITS_PER_LONG, bit +=
	BITS_PER_LONG, addr++) {
		if (~(*addr) == 0)
			continue;
		return (bit + __ffsl(~(*addr)));
	}
	if (size) {
		mask = ~(*addr) & BIT_MASK(size);
		if (mask)
			bit += __ffsl(mask);
		else
			bit += size;
	}
	return (bit);
}

static inline void bitmap_zero(unsigned long *addr, int size) {
	int len;

	len = BITS_TO_LONGS(size) * sizeof(long);
	memset(addr, 0, len);
}

static inline void bitmap_fill(unsigned long *addr, int size) {
	int tail;
	int len;

	len = (size / BITS_PER_LONG) * sizeof(long);
	memset(addr, 0xff, len);
	tail = size & (BITS_PER_LONG - 1);
	if (tail)
		addr[size / BITS_PER_LONG] = BIT_MASK(tail);
}
/*
 static inline int
 bitmap_full(unsigned long *addr, int size)
 {
 long mask;
 int tail;
 int len;
 int i;

 len = size / BITS_PER_LONG;
 for (i = 0; i < len; i++)
 if (addr[i] != ~0UL)
 return (0);
 tail = size & (BITS_PER_LONG - 1);
 if (tail) {
 mask = BIT_MASK(tail);
 if ((addr[i] & mask) != mask)
 return (0);
 }
 return (1);
 }

 static inline int
 bitmap_empty(unsigned long *addr, int size)
 {
 long mask;
 int tail;
 int len;
 int i;

 len = size / BITS_PER_LONG;
 for (i = 0; i < len; i++)
 if (addr[i] != 0)
 return (0);
 tail = size & (BITS_PER_LONG - 1);
 if (tail) {
 mask = BIT_MASK(tail);
 if ((addr[i] & mask) != 0)
 return (0);
 }
 return (1);
 }

 #define	__set_bit(i, a)							\
    atomic_set_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))
 */
/*
 #define	NBLONG	(8 * sizeof(long))
 #define	ARM_VECTORS_HIGH	0xffff0000U
 #define ARM_TP_ADDRESS		(ARM_VECTORS_HIGH + 0x1000)
 #define ARM_RAS_START		(ARM_TP_ADDRESS + 4)
 static __inline void atomic_set_32(volatile uint32_t *address, uint32_t setmask) {
 int start, ras_start = ARM_RAS_START;

 __asm __volatile("1:\n"
 "adr	%1, 1b\n"
 "str	%1, [%0]\n"
 "adr	%1, 2f\n"
 "str	%1, [%0, #4]\n"
 "ldr	%1, [%2]\n"
 "orr	%1, %1, %3\n"
 "str	%1, [%2]\n"
 "2:\n"
 "mov	%1, #0\n"
 "str	%1, [%0]\n"
 "mov	%1, #0xffffffff\n"
 "str	%1, [%0, #4]\n"

 : "+r" (ras_start), "=r" (start), "+r" (address), "+r" (setmask)
 : : "memory");
 }
 static __inline void atomic_set_long(volatile u_long *p, u_long v) {

 atomic_set_32((volatile uint32_t *) p, v);
 }
 #define	set_bit(i, a)							\
    atomic_set_long(&((volatile u_long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))
 */

///< the bitmap data type to store the bitmap elements
typedef unsigned long bitmap_data_t;

///< helper macro for
#define BITMAP_BITS_PER_ELEMENT (8 * sizeof(bitmap_data_t))

static __inline void set_bit(u_long v, volatile u_long *p) {
	bitmap_data_t data = p[v / BITMAP_BITS_PER_ELEMENT];
	data |= (1UL << (v % BITMAP_BITS_PER_ELEMENT));
	p[v / BITMAP_BITS_PER_ELEMENT] = data;
}

static __inline void clear_bit(u_long v, volatile u_long *p) {
	bitmap_data_t data = p[v / BITMAP_BITS_PER_ELEMENT];
	bitmap_data_t mask = 1UL << (v % BITMAP_BITS_PER_ELEMENT);
	data &= ~(mask);
	p[v / BITMAP_BITS_PER_ELEMENT] = data;
}

static __inline int test_bit(u_long v, volatile u_long *p) {
	bitmap_data_t data = p[v / BITMAP_BITS_PER_ELEMENT];
	return (data >> (v % BITMAP_BITS_PER_ELEMENT)) & 1;
}

/*
 #define	__clear_bit(i, a)						\
    atomic_clear_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))

 #define	clear_bit(i, a)							\
    atomic_clear_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))

 #define	test_bit(i, a)							\
    !!(atomic_load_acq_long(&((volatile long *)(a))[(i)/NBLONG]) &	\
    (1UL << ((i) % NBLONG)))

 static inline long
 test_and_clear_bit(long bit, long *var)
 {
 long val;

 var += bit / (sizeof(long) * NBBY);
 bit %= sizeof(long) * NBBY;
 bit = (1UL << bit);
 do {
 val = *(volatile long *)var;
 } while (atomic_cmpset_long(var, val, val & ~bit) == 0);

 return !!(val & bit);
 }

 static inline long
 test_and_set_bit(long bit, long *var)
 {
 long val;

 var += bit / (sizeof(long) * NBBY);
 bit %= sizeof(long) * NBBY;
 bit = (1UL << bit);
 do {
 val = *(volatile long *)var;
 } while (atomic_cmpset_long(var, val, val | bit) == 0);

 return !!(val & bit);
 }

 */
#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG))
#define BITMAP_LAST_WORD_MASK(nbits)                                    \
(                                                                       \
        ((nbits) % BITS_PER_LONG) ?                                     \
                (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL               \
)

static inline void bitmap_set(unsigned long *map, int start, int nr) {
	unsigned long *p = map + BIT_WORD(start);
	const int size = start + nr;
	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);

	while (nr - bits_to_set >= 0) {
		*p |= mask_to_set;
		nr -= bits_to_set;
		bits_to_set = BITS_PER_LONG;
		mask_to_set = ~0UL;
		p++;
	}
	if (nr) {
		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
		*p |= mask_to_set;
	}
}

static inline void bitmap_clear(unsigned long *map, int start, int nr) {
	unsigned long *p = map + BIT_WORD(start);
	const int size = start + nr;
	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);

	while (nr - bits_to_clear >= 0) {
		*p &= ~mask_to_clear;
		nr -= bits_to_clear;
		bits_to_clear = BITS_PER_LONG;
		mask_to_clear = ~0UL;
		p++;
	}
	if (nr) {
		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
		*p &= ~mask_to_clear;
	}
}

enum {
	REG_OP_ISFREE, /*true if region is all zero bits*/
	REG_OP_ALLOC, /*set all bits in region*/
	REG_OP_RELEASE, /*clear all bits in region*/
};

static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op) {
	int nbits_reg; /*number of bits in region*/
	int index; /*index first long of region in bitmap*/
	int offset; /* bit offset region in bitmap[index]*/
	int nlongs_reg; /*num longs spanned by region in bitmap*/
	int nbitsinlong; /*num bits of region in each spanned long*/
	unsigned long mask; /*bitmask for one long of region*/
	int i; /*scans bitmap by longs*/
	int ret = 0; /* return value*/

	/** Either nlongs_reg == 1 (for small orders that fit in one long)
	 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)*/

	nbits_reg = 1 << order;
	index = pos / BITS_PER_LONG;
	offset = pos - (index * BITS_PER_LONG);
	nlongs_reg = BITS_TO_LONGS(nbits_reg);
	nbitsinlong = min(nbits_reg, BITS_PER_LONG);

	/** Can't do "mask = (1UL << nbitsinlong) - 1", as that
	 * overflows if nbitsinlong == BITS_PER_LONG.*/

	mask = (1UL << (nbitsinlong - 1));
	mask += mask - 1;
	mask <<= offset;

	switch (reg_op) {
	case REG_OP_ISFREE:
		for (i = 0; i < nlongs_reg; i++) {
			if (bitmap[index + i] & mask)
				goto done;
		}
		ret = 1; /*all bits in region free (zero)*/
		break;

	case REG_OP_ALLOC:
		for (i = 0; i < nlongs_reg; i++)
			bitmap[index + i] |= mask;
		break;

	case REG_OP_RELEASE:
		for (i = 0; i < nlongs_reg; i++)
			bitmap[index + i] &= ~mask;
		break;
	}
	done: return ret;
}
/*
 *
 * bitmap_find_free_region - find a contiguous aligned mem region
 *      @bitmap: array of unsigned longs corresponding to the bitmap
 *      @bits: number of bits in the bitmap
 *      @order: region size (log base 2 of number of bits) to find
 *
 * Find a region of free (zero) bits in a @bitmap of @bits bits and
 * allocate them (set them to one).  Only consider regions of length
 * a power (@order) of two, aligned to that power of two, which
 * makes the search algorithm much faster.
 *
 * Return the bit offset in bitmap of the allocated region,
 * or -errno on failure.
 */
static inline int bitmap_find_free_region(unsigned long *bitmap, int bits,
		int order) {
	int pos, end; /*scans bitmap by regions of size order*/

	for (pos = 0; (end = pos + (1 << order)) <= bits; pos = end) {
		if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
			continue;
		__reg_op(bitmap, pos, order, REG_OP_ALLOC);
		return pos;
	}
	return -ENOMEM;
}
/*
 *
 * bitmap_allocate_region - allocate bitmap region
 *      @bitmap: array of unsigned longs corresponding to the bitmap
 *      @pos: beginning of bit region to allocate
 *      @order: region size (log base 2 of number of bits) to allocate
 *
 * Allocate (set bits in) a specified region of a bitmap.
 *
 * Return 0 on success, or %-EBUSY if specified region wasn't
 * free (not all bits were zero).


 static inline int
 bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
 {
 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
 return -EBUSY;
 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
 return 0;
 }

 *
 * bitmap_release_region - release allocated bitmap region
 *      @bitmap: array of unsigned longs corresponding to the bitmap
 *      @pos: beginning of bit region to release
 *      @order: region size (log base 2 of number of bits) to release
 *
 * This is the complement to __bitmap_find_free_region() and releases
 * the found region (by clearing it in the bitmap).
 *
 * No return value.

 static inline void
 bitmap_release_region(unsigned long *bitmap, int pos, int order)
 {
 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
 }


 #define for_each_set_bit(bit, addr, size) \
	for ((bit) = find_first_bit((addr), (size));		\
	     (bit) < (size);					\
	     (bit) = find_next_bit((addr), (size), (bit) + 1))
 */

#endif	/* _LINUX_BITOPS_H_ */